1. Field of the Invention
The invention relates generally to gas transportation systems and, more particularly, relates to a system for transporting non-liquefied compressed gas over water.
2. Description of the Relevant Art
Several varied distribution systems for natural gas are well known. Pipelines are generally used to economically distribute compressed natural gas (CNG) over land. Pipelines are large systems that require planning, large capital investement, and are subject to regulatory control. Due to this regulatory control, and other factors, pipeline technology is highly standardized and well understood. Pipeline materials, such as standard pipeline type pipe, are used in great quantities and are economically mass produced.
A system for transporting natural gas from "shut in" wells not accessed by a pipeline is disclosed in U.S. Pat. Nos. 4,139,019, 4,213,476, and 4,380,242. Those patents disclose a system for transferring CNG from a shut in well to a delivery point in special containers carried by a truck.
Systems for transporting natural gas over water generally include ships having special vessels on board for storing liquefied natural gas (LNG). The quantity of gas transported is of course much greater if the gas is liquefied. The high cost of building and operating over-water transport can only be recovered by transporting LNG. However, an LNG transport system requires a liquefaction facility at the shipping point and a conversion facility at the delivery point.
In many instances, geography dictates that over water transport is desirable. For example, gas may be transported from a source on one island to a user on another island or inadequate roads and lack of a pipeline make transportation by rivers desirable. However, the amount of gas to be transferred, or other factors, may not justify the costs of liquefaction and liquid handling facilities or the construction of a pipeline. Thus, economical transport of CNG over-water is required.
Several systems have been proposed to implement this type of system. In one system, the above-described CNG truck transport system is transported by barge. Also, a system utilizing special custom-built vessels for storing CNG on the deck of a barge has been proposed.
All of the proposed systems have some drawbacks either in the cost of the system, safety problems, or lack of capacity. However, the various proposals illustrate the need for an economically viable system for over-water transportation of CNG.